Using 2 Inductive Z-Probes

I'm about to start assembling my custom IDEX (Independent Dual Extrusion) machine and I plan to use inductive probes to calibrate the Z offset for each tool head. My question is how to wire two PNP inductive sensors and configure the firmware for them.

For leveling I plan to probe the bed at 3 points with the first tool head to compensate for tilt and to gauge the Z offset, then use the second tool to probe the center of the bed to calculate the Z offset for the second tool head. I'd like to use the calculation of the tilt done by the first head for both tools (i.e. instead of probing 3 points with both tools which might give slightly different tilt calculations)

This will essentially allow me to use tools with different Z heights (i.e. E3D V6 and Volcano). I understand that I give up the ability to dual print.

The only input that is suitable for use with PNP output sensors is the Z probe input (with 2 resistors to reduce the voltage). So you would need external circuitry to switch between them. Whereas NPN output sensor can be connected to 3 different endstop inputs, which you can select using M558.

The only input that is suitable for use with PNP output sensors is the Z probe input (with 2 resistors to reduce the voltage). So you would need external circuitry to switch between them. Whereas NPN output sensor can be connected to 3 different endstop inputs, which you can select using M558.

Okay so lets say I use two NPN sensors instead. How would I go about wiring and configuring them both if I'm using the E0 input for the U axis limit switch?

The only input that is suitable for use with PNP output sensors is the Z probe input (with 2 resistors to reduce the voltage). So you would need external circuitry to switch between them. Whereas NPN output sensor can be connected to 3 different endstop inputs, which you can select using M558.

Okay so lets say I use two NPN sensors instead. How would I go about wiring and configuring them both if I'm using the E0 input for the U axis limit switch?

Use the E1 endstop input for one of them. For the other, use the Z endstop input if it is free, or the Z probe input.